The vote for industrial action was prompted by skirmishing over rosters and the fallout from the closure of an Aer Lingus cabin crew base at Shannon.

The cabin staff are members of the IMPACT union and voted 91pc in favour of action in a ballot. The union will make a decision in regard to its next move in coming days.

An IMPACT spokesman described a strike as "a distinct possibility".

It is the latest in a series of dramatic strike threats from various Aer Lingus employee groups. Last August its pilots made noises about striking in support of Aer Arann pilots protesting over pay.

In June, pilots threatened action over increments, with union sources warning of strikes over the crucial summer travel period.

In October of last year unions also threatened to shut down the airline over a pensions row. A planned two-hour shutdown was called off at the last minute.

The long-running dispute between staff and Aer Lingus management centres on the huge hole in the airline's pension fund.

PENSION

Staff at the former state airline are part of a joint pension scheme with airport operator DAA. The scheme has a deficit of close to €780m, which means that it simply cannot pay out expected pension benefits unless it is dramatically restructured.

This may lead to reduced pension payments for existing and former staff who have not yet retired.

The restructuring of the pension scheme has been under discussion for a number of years. Following its 2006 stock-market flotation, Aer Lingus made a one-off €104m payment to settle its pension fund deficit.

But it did little to satisfy the unions and industrial relations unrest has simmered since.

Labour Court proposals last May looked to have settled the issue, with Aer Lingus poised to pay more than €110m to help plug the deficit. But that did not pacify the unions, who wanted a bigger contribution.

A strike – or even the threat of a strike – has the potential to cause real damage to the airline's revenues in the run-up to the key Christmas travel period.

Shares in the airline fell as much as 9pc yesterday. However, the bulk of the share price fall came before news of the strike ballot emerged.